Pneumatic fluidizing means



Dec. 14, 1965 D. ALBERT 3,223,457

PNEUMATIC FLUIDIZING MEANS Filed Jan. 29, 1964 INVENTOR.

DOUGLAS ALBERT BY ATTORNEYS 3,223,457 PNEUMATZC FLUEDEZZNG MEANS DougiasAibert, @airland, Caiitl, assignor to Albert Air Qonveyor Corp, @aidand,Caliii, a corporation of Nevada Filed Jan. 29, 1964, Ser. No. 340,925 5Claims. (Cl. 3tl2-53) This invention relates to an improved apparatusfor aiding the removal of pulverant material from a storage vessel. Moreparticularly this invention relates to an improved pneumatic fluidizingapparatus which is used to aid the discharge of pulverant materials fromthe storage tank.

The pneumatic removal of pulverant materials, such as gravel, salt, andflour from a hopper can be accomplished by aerating or fluidizing thelowermost portion of the material located in the vicinity of the hopperoutlet with pressurized air. By directing the pressurized air into thismass of pulverant material, the flowability of the material is increasedand any tendency for the materials to compact and block the hopperoutlet or to remain trapped on the hopper walls is substantiallyreduced.

Heretofore, fluidizing or aerating has been accomplished by means offluid pervious pads connected as integral part of the hopper walls.Normally, these fluid pervious pads included a skin or membrane ofrubber-like material which let air into the chamber to aerate orfluidize the pulverant material when a pressure differential existedacross the membrane. As a result of the fluidization, the flowability ofthe pulverant material discharge through a hopper outlet opening wasincreased. Although this type of pad was well suited for finer materialsit was not especially etlicient when coarse, pebbly, or gravelly typepulverant materials were handled. In this latter situation there was atendency for the fluidizing air to flow past the material at times whenthe pad started to become uncovered. As a result, the material couldremain on the hopper walls or become compacted and bridge over theoutlet opening. In addition, the pad by necessity of its design andcharacteristics formed an irregular area on the normally smooth hopperwall surface thereby creating a material trapping area. When materialwas so trapped on such areas or in the hopper, it was possible for acustomer to receive a short load for which he was charged. In additionresidual material could cause contamination problems especially when acaustic material was carried on one load and edible food products werecarried on subsequent loads. In such cases, residual material removalnormally required an auxiliary cleaning operation such as flowing asudden blast of pressurized air into the tank.

Accordingly, it is an object of this invention to solve the aboveproblems by locating the fluidizing elements above and spaced from thehopper walls.

The advantage of this arrangement resides in the fact that the surfaceof the hopper walls is uninterrupted and smooth thereby substantiallyeliminating fluid trapping areas thereon.

An advantage of this arrangement resides in the fact that the fluidizingfluid can be directed in an efiicient pattern which effectively cleansthe hopper valleys or corners formed at the abutment or intersection ofthe flat walls of the hoppers.

Another object of this invention is to provide a suspended fluidizer ofthe above type in which the fluidizing elements are arranged in aradially extending spoke-like configuration extending from the axis ofthe pressure vessel toward the hopper walls and toward the hopper wallvalleys or corners to direct the fluidizing air in a more effectivepattern for clean-out of the fiat sloping wall portions to the hopperand the hopper valleys.

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Yet another object of this invention is to provide an improvedfluidizing element for the above type of fluidizer which includes aperforated pipe having a jacket of woven fibers, which is pervious tothe pressurized fluid and impervious to the pulverant material, snuglysecured about the pipe in an easily detached arrangement to fluidize oraerate the pulverant material contained in the hopper when pressurizedfluid is directed into the pipe.

An advantage resides in the fact that the jacket can be readily detachedthereby permitting harsh solvents or chemicals to be used for cleaningthe pressure vessel interior. Another advantage of easy jacket removalresides in the fact that one set of jackets can be removed and replacedwith another set of jackets to eliminate contamination problems whichmight arise due to incompatible materials having previously becomeingrained in the jacket fabric wherein a subsequent load would bedeleteriously affected by the ingrained material.

Another advantage of easily detachable jackets is that the same set ofjackets can be removed and stored for reuse when fluidizing the samematerial at some later time thereby eliminating the need for cleaningthe fluidizing jackets or surface or any ingrained or adhered materialswhen incompatible materials are to be handled on subsequent loads.

Still another object of this invention is to provide a seamless wovenfabric jacket which is connected about a fluid distributing pipe, thejacket being pervious to the pressurized fluid when a pressuredifferential exists across the fabric but which jacket is impervious tothe pulverant material when the pressure within the pipe decreases.

Other objects, features, and advantages of this invention will becomeapparent upon reading the following detailed description and referringto the accompanying drawings in which:

FIGURE 1 is a side elevational view showing one embodiment of thefluidizing means connected in the hopper of a pressurized storagevessel;

FIGURE 2 is a side elevational view of a second embodiment of thefluidizing means connected in a hopper;

FIGURE 3 is a top plan view of the spoke like fluidizing elementarrangement of FIGURE 2; and

FIGURE 4 is an enlarged perspective view of the lower fluidizingelements in which a portion of one woven fiber jacket is broken away toshow the enclosed perforated fluid distributing pipe.

An illustrated in FIGURE 1, there is provided a representativepressurized storage vessel 12 having a hopper floor 13 and a dome-likelid 14. A scalable access door 15' is provided in the lid for depositingpulverant material such as gravel, stones, sand, salt, or flour withinthe vessel chamber. Once vessel 12 is filled access door 15 is sealed inan airtight fit. It should be noted at this time that the vertical orupright vessel 12 is meant to be representative of the various types ofpressurized storage vessels which can be used. Hopper 13 has slopingside walls which tend to gravitationally feed the pulverant materialtoward outlet valve re. With outlet valve 16 closed the storage vesselis eflectively a sealed closed storage chamber.

During the fluidizing operation outlet valve 16 is opened to provide apath for pulverant material transfer from the storage vessel interior tothe connected horizontal material discharge pipe 18. By openingdischarge control valve 19, a pressurized stream of air is directedthrough discharge pipe 18 to carry away any pulverant material whichdrops through outlet valve 16. Of course, it should be understood thatan alternate material removal arrangement could be used such as agravity discharge valve 22 connected directly below the vessel outletvalve 16. In such cases, the outlet portion of the main materialdischarge conduit or pipe 18 would not be necessary. A portion ofpressurized air branches into fluidizing supply line and is directedthrough the vessel storage chamber along the chamber axis and into thefluidizer 21 suspended within the hopper from the lower end of airsupply pipe 20. While pulverant material is falling free of the hopperthe pressurized fluid supplied to the fluidizing elements 30a, 36:! and31a-3ld is directed into the pulverant material to fluidize or aerate itthereby making it more flowable and insuring ready material removalthrough the hopper outlet without the attendant problems of thepulverant material compacting and bridging across the outlet andpreventing further removal of material.

In order to equalize the pressure in the air space at the top ofpressurized storage chamber 12 it may be necessary to provide a ventmeans 25 having a valve 26 connected therein for effectively opening andclosing a path for venting fluid communication with main materialdischarge pipe 18.

Now referring to fluidizer 21, it is seen that the fluidizing elementsor arms a through 30d and 31a through 31d are suspended within the lowerportion of the hopper and spaced above the hopper walls. As pressurizedfluid is directed through the fluid supply pipe 20 the fluid branchesinto these arms and escapes or is directed through the fluid perviousjackets and fluidizes or aerates the pulverant material contained withinthe hopper, as will be explained in more detail shortly.

Before describing the details of the fluidizer elements, reference isfirst made to the second embodiment of the invention illustrated inFIGURES 2 and 3. Here pressurized fluid supply pipe 20 is connectedhorizontally between two of the sloping hopper walls by welding or anyother suitable leak-proof method. One end of air supply pipe 20 isblocked or sealed by the hopper wall 28 and the other end of the supplypipe extends through an aperture in hopper wall 29 to a supply of fluid.Pressurized fluid can be supplied to pipe 20 in much the same manner asdescribed in reference to the embodiment of FIGURE 1. As more clearlyillustrated in the top plan view of FIGURE 3 the hopper walls form aninverted pyramid with valley, or corners, being formed at the abutmentof each triangular wall portion. As previously stated, these valleyshave a tendency to retain the pulverant material during the dischargeoperation or emptying of the hopper. And as previously stated indescribing the prior problems it can be seen that a fluidizing padforming part of a hopper wall will not provide a fluidizing air patternwhich will effectively fluidize material retained in these valleys.

In order to overcome these problems, the fludizing elements of thisinvention can be arranged spaced from and above the hopper walls inupper and lower sets. Those arms or elements 31a through 31d in thelower set are radially directed from vertical fluid supply hub or crossfitting 36 toward the valleys. By so directing this lower set of arms31a through 31d into the hopper corners it is possible to take advantageof the increased linear dimension which occurs between diametricallyopposite valleys. As a result, a relatively long fluidizing element canbe employed thereby greatly increasing the fluidizing efficiency of thesystem. The upper set of fluidizing elements or arms 30a through 30dproject radially from the vertical fluid supply hub 36 at an angulardisplacement relative to the lower set of radially projecting fluidizingelements. Because of the sloping nature of the hopper walls and theresultant increase in radial dimension it is possible to direct theupper set of fluidizing elements or arms directly toward the flat hopperwalls, As a result it is possible to provide fluidizing elements whichare the same length as the lower set of fluidizing elements and in whicheach set effectively fluidizes material at different portions of thehopper.

Now referring to the details of the fluidizer structure illustrated inFIGURE 4, the side-inlet, cross fitting 35,

is representative and has been illustrated broken away from the upperside inlet cross fitting. Each cross arm projects at a right angle tothe adjacent arms and is threaded at the end for threaded connectionwith individual ones of four perforated pipes 38. Each perforated pipe38 is capped or plugged at its outermost end and provides distributingpaths through the perforations for pressurized fluid. The material usedfor fitting 35 and the perforated pipes 38 should be of any conventionalipe material which is capable of withstanding the internal pressures ofthe pressurized fluid and supporting the weight of the pulverantmaterial dumped into the hopper.

In order to insure a relatively even distribution of the pressurizedfluid during the fluidizing operation and to prevent entry of thepulverant material into the pipes by way of the pipe perforations awoven fiber jacket 40 is snugly slipped over each perforated pipe 38 andsecured thereto by means of a quick coupling fastener 39. One type offastener which could be used would be the trademarked Kamlock fastenerwhich has two depressible members connected for fastening or releasingthe sleeve flange. The woven jacket 40 is preferably seamless and mustbe pervious to the pressurized fluid within the pipes 38 when asuflicient pressure differential exists across the jacket material butimpervious to the pulverant material when the fluid pressure withinperforated pipe 33 is reduced. The particular fibers used in the wovenmaterial can include asbestos, canvas, natural fibers, synthetic fibersor any combination. A combination of asbestos and canvas has been foundto be especially effective.

As previously stated, the advantage of a quick disconnect and wovenfiber jacket resides in the fact that jackets 40 can be disconnectedwhen they become ingrained or contaminated with the residue of pulverantmaterial and a clean one substituted. In addition, different sets ofjackets can be always kept on hand which are always used on the samepulverant material, i.e., one set would always be used on causticmaterials and another set would be used on flour. The normally fluidabsorbent fiber jackets can also be removed at such time as the vesselinterior is to be cleaned with solvents or detergents. This removalgreatly simplifies the cleaning operation and eliminates the expense ofreplacing jackets which can be operationally destroyed by the cleaningmaterials.

Although several embodiments of this invention have been described andillustrated in detail for purposes of description it should beunderstood that other changes can be made in the invention withoutdeparting from the scope thereof as defined in the appended claims.

What is claimed is:

1. An improved apparatus for handling pulverant material comprising: ahollow tank including a hopper having a sloping wall secured to thebottom thereof; outlet means connected to the lowermost portion of thehopper for discharging pulverant material from said tank; asubstantially vertically extending gaseous fluid supply means connectedto direct pressurized gaseous fluid into said tank; and a plurality ofhollow fluid distributor means having terminal ends spaced apart fromand above said sloping wall, each said terminal end having a wallportion including fabric of the type which is pervious to pressurizedfluid and impervious to pulverant material, means for removably mountingsaid fabric to said fuel distributor means, said distributors beingconnected to project in radially spaced apart relation from the fluidsupply means to fluidize the pulverant material with the pressurizedfluid for subsequent discharge of the fluidized material through saidoutlet means.

2. The improved apparatus for handling pulverant material of claim 1 inwhich said hollow fluid distributors each project horizontally from thefluid supply means in a zone within the hopper and above the outletmeans.

3. The improved apparatus for handling pulverant material of claim 2 inwhich some of said plurality of fluid distributors are connected toradiate from the fluid supply means at a first vertical level and theremaining fluid distributors are connected to radiate from said fluidsupply means at a second vertical level and in which the distributors ofone level are angularly displaced from the distributors on the otherlevel.

4. An improved apparatus for handling pulverant material comprising: apressure vessel having a hopper floor secured thereto; said vessel beingoperable to store pulverant material; outlet means connected todischarge the pulverant material from said vessel at the lowermostportion of said hopper; fluid supply means connected to directpressurized fluid into said vessel along the central vertical axisthereof; a plurality of distributor pipes connected in fluidcommunication with said fluid supply means above and spaced from thehopper wall to direct the pressurized fluid in a zone within the hopper;each said pipe being perforated along a portion of its length remotefrom said fluid supply means to permit release of pressurized fluidtherethrough; a jacket of woven fiber which is pervious to thepressurized fluid and impervious to the pulverant material disposedaround each said perforated pipe portion to fluidize the pulverantmaterial in the hopper zone;

and means for rernovably connecting said jacket to said pipe.

5. The improved apparatus for handling pulverant material of claim 4 inwhich the hopper has flat walls and forms an inverted pyramid and saidplurality of fluid distributor pipes are the same length and arearranged in an upper and a lower horizontally extending zone and inwhich the individual pipes in the lower zone project toward each of thepyramid corners and in which the individual pipes of the upper zone areangularly displaced relative to the lower pipes to project toward thehopper wall.

References Cited by the Examiner UNITED STATES PATENTS 2,815,987 12/1957Sylvest 302-29 2,924,489 2/1960 Beckman 30253 2,989,349 6/1961 Hartley302-53 3,121,593 2/1964 McIlvaine 302-53 FOREIGN PATENTS 1,145,5493/1963 Germany.

607,009 8/ 1948 Great Britain.

SAMUEL F. COLEMAN, Primary Examiner.

1. AN IMPROVED APPARATUS FOR HANDLING PULVERANT MATERIAL COMPRISING: AHOLLOW TANK INCLUDING A HOPPER HAVING A SLOPING WALL SECURED TO THEBOTTOM THEROEF; OUTLET MEANS CONNECTED TO THE LOWERMOST PORTION OF THEHOPPER FOR DISCHARGING PULVERANT MATERIAL FROM SAID TANK; ASUBSTANTIALLY VERTICALLY EXTENDING GASEOUS FLUID SUPPLY MEANS CONNECTEDTO DIRECT PRESSURIZED GASEOUS FLUID INTO SAID TANK; AND A PLURALITY OFHOLLOW FLUID DISTRIBUTOR MEANS HAVING TERMINAL ENDS SPACED APART FROMAND ABOVE SAID SLOPING WALL, EACH SAID TERMINAL END HAVING A WALLPORTION INCLUDING FABRIC OF THE TYPE WHICH IS PERVIOUS TO